1. Field of the Invention
This invention relates to disk drive suspensions, and more particularly to disk drive suspensions of the chip-on-suspension type where the preamp microchip signal processor is carried in the load beam rigid portion. The invention further relates to mounting the microchip in a lower profile, more spaced from the disk position within an opening in the suspension load beam rigid portion, where the microchip is supported against spurious vibration.
2. Related Art
The mounting of a disk drive recording head or slider (a term used herein to include both the recording head and the slider body in which the head is mounted) is typically at the distal end of the suspension. The suspension itself is mounted on an actuator arm. The preamp microchip has usually been located on the actuator because of overall performance and cost considerations, although this location may expose the costly chip to the possibility of being damaged during staking operations.
As the signals being processed by the recording head increase in frequency and decrease in amplitude, however, the remoteness of the preamp microprocessor to the head becomes problematic, and so-called chip-on-suspension techniques are used to put the preamp microchip and recording head closer together to minimize ambient interferences with the signals.
Locating the microchip on the suspension is not without difficulties, however. Thus, mounting the preamp microchip at the far distal end of the suspension, adjacent the slider, leaves the microchip prone to damage from head slap resulting from lift-off and landing shocks. In addition, the heat radiating from the microchip can interfere with the thermally sensitive MR and GMR sliders. Windage interactions of the microchip are also negative factors, particularly since the fluid dynamics cross-section effect of the microchip is multiplied by the long moment arm between the microchip and the attachment point at the actuator.
Mounting the preamp microchip midway on the suspension at the rigid portion of the load beam offers potentially better shock and resonance performance. Use of the location, however, is constrained by the need to maintain minimum clearances in this area for combing operations (mechanical separation of the disks and load beams, e.g. in head stack assembly). Too little clearance chances damage to the disk since it is necessary to maintain a certain minimum strength (and thus size) in the combs to effectively lift the suspension from the disk. But the microchip is comparatively bulky in suspension terms.
It is accordingly an object of this invention to provide a disk drive suspension having the preamp microchip in the optimum location for high frequency, low amplitude signals, midway along the suspension, while avoiding the problems noted above. It is a further object to provide a disk drive suspension in which the microchip is mounted to the load beam rigid portion in such a way as to afford greater clearance from the disk for ease of combing operations. It is a still further object to provide a modified load beam for a disk drive suspension in which the preamp microchip is within the profile of the load beam rails against comb damage, and has a portion of its height within the load beam height rather than cumulative to the load beam height, and the flexible circuit conductor in the disk direction, thereby increasing the amount of space available for the combs to operate. It is another object to adhere the microchip to the load beam rather than to merely the flexible circuit conductor to reduce spurious vibrations found in an unsupported mass of the microchip on the conductor. Yet another object is to avoid having the microchip face the disk and risk contact of the microchip and the disk. A further object is to eliminate the windage problem noted above, by placing the microchip largely between the suspension edge rails. Another object is to facilitate high combing force, easy cleaning, and ready mergence of head and disk by increasing the disk-to-microchip spacing. The invention further has the object of facilitating automated attachment of the microchip onto the flexible circuit conductor or conductive traces by upward exposure of the contact points. It is a further object to provide a method of assembling disk drive suspensions having the advantages just noted.
These and other objects of the invention to become apparent hereinafter are realized in a disk drive suspension for supporting a slider in operating proximity to a disk, the suspension comprising a load beam having a base portion, a spring portion and a rigid portion, the load beam rigid portion having a first side proximate to the slider, a second side remote from the slider and a predetermined thickness between the first and second sides, a conductor defining a locus of electrical contact along the extent of the load beam rigid portion, and a signal-processing microchip extending through the rigid portion predetermined thickness, the microchip being electrically connected to the conductor at the electrical contact locus.
In this and like embodiments, typically, the load beam rigid portion has opposed edge rails on its remote side, the microchip being located between the edge rails, the microchip is generally polygonal, the load beam rigid portion having a microchip-receiving opening larger and generally congruent with the microchip, the opening extending through the rigid portion predetermined thickness, the conductor comprises a flexible circuit, the flexible circuit conductor is located on the rigid portion first side and defines the locus of electrical contact opposite the microchip, the flexible circuit conductor is supported by the load beam rigid portion and defines a flexure for supporting the slider, the flexible conductor supports the microchip in its load beam rigid portion received relation, the locus of electrical contact is a center locus, the flexible circuit also defining a proximate locus of electrical contact at the load beam base portion, and a distal locus of electrical contact at the slider for coupling the microchip to the slider and to electrical contact pads at the base portion, and/or the microchip is adhesively attached to the load beam rigid portion.
In a preferred embodiment, the invention provides a disk drive suspension for supporting a slider in operating proximity to a disk, the suspension comprising a stainless steel load beam having a base portion, a spring portion and a rigid portion, a slider mounted on a first side of the rigid portion, and a microchip mounted on a second side of the rigid portion.
In this and like embodiments, typically, the load beam rigid portion defines a microchip receiving opening, the microchip being adhesively bonded in the opening, the microchip has a given height, the height being such that the microchip is not fully received within the load beam rigid portion opening and has a projecting section beyond the rigid portion second side, the rigid portion second side having edge rails on opposite sides of the microchip, the microchip projecting section projecting from the rigid portion second side no higher than the edge rails, the microchip is generally polygonal, the load beam rigid portion having a microchip-receiving opening larger and generally congruent with the microchip, the opening extending through the thickness of the rigid portion, the suspension further comprises a conductor extending along the load beam rigid portion first side, the conductor comprises a flexible circuit having conductive traces and dielectric plastic laminated to a steel layer, the flexible circuit conductor being attached to the load beam rigid portion, the flexible circuit conductor is located on the rigid portion first side and defines a locus of electrical contact opposite the microchip, the flexible circuit conductor defines a flexure supporting the slider, the flexible conductor supports the microchip in its load beam rigid portion received relation, the conductor defines a locus of electrical contact for electrical connection of the conductor to the microchip, the suspension further includes electrical contact pads at the load beam base portion and at the slider, and in which the conductor locus of electrical contact is a center locus, the flexible circuit also defining a proximate locus of electrical contact at the load beam base portion, and a distal locus of electrical contact at the slider for coupling the microchip to electrical contact pads at the slider and to electrical contact pads at the base portion, and/or the microchip is adhesively attached to the load beam rigid portion.
In a particularly preferred embodiment, the invention provides a disk drive suspension supporting a slider in operating proximity to a disk, the suspension comprising an elongated load beam having in outward sequence a generally rectangular base portion mounted to an actuator with a mounting plate, a spring portion and an outwardly tapered rigid portion having a wider part adjacent the spring portion, the rigid portion wider part having an opening, and a narrower part adjacent the slider, and left and right edge rails terminating at the distal end of the load beam, the load beam rigid portion having a first side proximate to the slider and a second side remote from the slider and carrying the edge rails, a flexible circuit conductor fixed to the load beam rigid portion first side and comprising a dielectric layer, a plurality of conductive traces on the dielectric layer, a spring metal supporting layer, and a dielectric plastic cover over the conductive traces, the flexible circuit conductor defining a center locus of electrical contact comprising a plurality of contact pads located along the wider part of the load beam rigid portion, and a signal-processing microchip adhesively mounted within the rigid portion wider part opening, the microchip extending from the rigid portion second side through to the rigid portion first side portion, the microchip being electrically connected to the contact pads at the center locus; the flexible circuit defining a proximate locus of electrical contact comprising base portion electrical contact pads and a distal locus of electrical contact at the slider comprising slider electrical contact pads, and the flexible circuit spring metal layer defining a flexure support for the slider.
In its method aspects, the invention provides a method for assembling a disk drive suspension having a microchip mounted to its rigid portion and a flexible conductor extending along the rigid portion length, including forming a through opening in the rigid portion, mounting the microchip in the opening, and electrically connecting the microchip to the flexible conductor in its through opening-mounted condition.